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Geokon 1100 Instruction Manual

Borehole extensometer
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Instruction Manual
Model 1100
Borehole Extensometer
No part of this instruction manual may be reproduced, by any means, without the written consent of GEOKON
®
.
The information contained herein is believed to be accurate and reliable. However, GEOKON
®
assumes no responsibility for
errors, omissions, or misinterpretations. The information herein is subject to change without notification.
Copyright © 2022 by GEOKON
(Document Revision A.1, 05/01/2023)
®

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Summary of Contents for Geokon 1100

  • Page 1 Instruction Manual Model 1100 Borehole Extensometer No part of this instruction manual may be reproduced, by any means, without the written consent of GEOKON ® The information contained herein is believed to be accurate and reliable. However, GEOKON ® assumes no responsibility for errors, omissions, or misinterpretations.
  • Page 3 Upon examination by GEOKON, if the unit is found to be defective, it will be repaired or replaced at no charge. However, the WARRANTY is VOID if the unit shows evidence of having been tampered with...
  • Page 5 2.1.1 P/N 1100-TOOLKIT (Set of installation tools) ..................9 2.1.2 P/N 1100-RECESSED-TOOLS (Accessories for recessed installations) ..........9 2.1.3 P/N 1100-GROUT-DOWN (Accessories for inclined downward installations) ........9 2.1.4 P/N 1100-GROUT-UP (Accessories for overhead/upward installations) ..........9 ............................10 OREHOLE IAMETER 2.2.1...
  • Page 6 C.1 S .........................32 INGLE RANSDUCER IRING HART C.2 T ..........................32 RANSDUCER IRING HART C.3 T ........................32 HREE RANSDUCERS IRING HART C.4 F .........................32 RANSDUCERS IRING HART C.5 F ...........................33 RANSDUCERS IRING HART C.6 S ..........................34 RANSDUCERS IRING HART APPENDIX D. SWAGELOK TUBE FITTING INSTRUCTIONS ................35 D.1 I ...............................35 NSTALLATION...
  • Page 7 1 THEORY OF OPERATION Introduction Borehole extensometers are used for monitoring displacements along the axis of the instrument in various applications (tunnels, shoring sidewalls, earthen dams, landslides, etc.) A series of borehole anchors interconnected by fiberglass, composite/graphite, or stainless steel connecting rods are installed at predetermined depths, with the deepest anchor installed in stable ground to serve as a nonmoving reference point.
  • Page 8 1.2.1 Head Assembly Figure 1 - Four Main Components of the Extensometer...
  • Page 9 The extensometer head assembly houses and protects the VW displacement transducers. The head assembly includes the following components: Protective cap • Side-exit cable (custom top exit available) • PVC coupling (or flange) • PVC standpipe. • Figure 2 - Main Components of the Head Assembly Head assembly sizes vary and are dependent upon the quantity and range of VW displacement transducers.
  • Page 10 Figure 3 - Slip Location for Inline Slip Couplings 1.2.3 Vibrating Wire Displacement Transducers GEOKON Model 4450 Vibrating Wire Displacement Transducers consist of a vibrating wire sensing element, in series with a heat treated, stress relieved spring. One end of the spring is connected to a vibrating wire, the other end to the transducer shaft.
  • Page 11 The standard ranges of VW displacement transducer which can be installed in the extensometer are: 12.5 mm (0.5 inch), 25 mm (1 inch), 50 mm (2 inch), 100 mm (4 inch), 150 mm (6 inch), 200 mm (8 inch) & 300 mm (12 inch). Figure 4 –...
  • Page 12 Note: Fiberglass rods have a lower modulus of elasticity than stainless steel rods. This, combined with friction effects, may lead to insufficient precision in applications where high resolution (< 0.1 mm) is required. Fiberglass rods are more stable thermally and can be a better choice than stainless steel rods in areas where temperatures may vary.
  • Page 13 it to expand and unwind. The soft copper material of the bladder allows it to deform and fill the space between the plastic spool and the borehole wall, thus wedging the anchor in place. The deformation of the copper bladder is permanent; and the anchor will stay in place even if the check valve fails.
  • Page 14 1.2.5.3 Single or Double Hydraulic Borros Anchor Hydraulic borros anchors are a type of end-bearing anchor recommended for soft soils. Hydraulically actuated prongs, spaced 120º from one another, penetrate the walls of the borehole, ensuring positive end-bearing anchorage. Single borros anchors (Figure 7) have three prongs located on the bottom end of the anchor;...
  • Page 15 Part Number Description Quantity B4450-49 Setting Tool Wrench HRD-A1663 3/16 inch T-handle Allen wrench, 25 inches Long 2.1.3 P/N 1100-GROUT-DOWN (Accessories for inclined downward installations) Part Number Description Quantity HRD-A1064 Hose Barb, 5/8 inch x1/2 inch, NPT HRD-A1068 Gate Valve, ½ inch, Bronze, NPT 2.1.4 P/N 1100-GROUT-UP (Accessories for overhead/upward installations)
  • Page 16 Borehole Diameter Boreholes should be drilled slightly deeper than the deepest anchor and cleared of debris before use. The mouth of the borehole can be enlarged (over-cored) or left as is, depending on installation requirements of the extensometer and project. 2.2.1 Extensometers without an Over Core The minimum borehole diameter for extensometers without an over core is determined by the number of points included in the head assembly.
  • Page 17 2.2.2 Extensometers Recessed in an Over Core Borehole 2.2.2.1 Over Core Depth The over core depth can be determined using Table 3. Table 3 references the length of the head assembly, which can be determined using the information in Appendix A, Section A.4 Head Assembly.
  • Page 18 12.5, 25, 50 mm (0.5, 1, 2 inch) 378 mm (14.88 inch) 381 mm (15.00 inch) 100 mm (4 inch) 479 mm (18.88 inch) 482 mm (19.00 inch) 200 mm (8 inch) 619 mm (24.38 inch) 622 mm (24.05 inch) 300 mm (12 inch) 772 mm (30.38 inch) 775 mm (30.50 inch)
  • Page 19 The cable can be protected using flexible conduit, which can be supplied by Geokon. Terminal boxes with sealed cable entries are available from Geokon for all types of applications. These allow many gauges to be terminated at one location with complete protection of the lead wires.
  • Page 20 Splice kits recommended by Geokon incorporate casts, which are placed around the splice and are then filled with epoxy to waterproof the connections. When properly made, this type of splice is equal or superior to the cable in strength and electrical properties. Contact Geokon for splicing materials and additional cable splicing instructions.
  • Page 21 3 ASSEMBLY AND INSTALLATION PLEASE NOTE: PVC primer and cement must be obtained locally. Airfreight restrictions prohibit GEOKON from shipping these materials. Preparation Prepare an area near the borehole for unpacking and assembling the extensometer. This should be done on a flat, dry surface, which has been covered with blankets, tarps, or similar. Use caution when unpacking the extensometer to avoid damaging sensitive components.
  • Page 22 For Borros Anchors: Using thread locker, screw the female threaded end of the connecting rod onto the setscrew located in the top of the Borros anchor. Figure 16 shows the completed assembly. Figure 14 - Groutable Anchors...
  • Page 23 Figure 15 - Bladder Anchors...
  • Page 24 Figure 16 Borros Anchors...
  • Page 25 3.2.2 For All Anchor Types: Slide one, 0.54 inch outside diameter 1/4 inch SCH 40 PVC pipe over the completed connecting rod column. Alternate attaching SS rods and PVC pipe based on desired depth. Glue the pipe into the adapter coupling on top of the anchor using PVC primer and cement. Allow sufficient time for the cement to harden.
  • Page 26 3.2.3 Fiberglass Connecting Rods To uncoil the bundle of fiberglass rods, carefully cut one tape wrapping after another, sequentially around the bundle. Do not try to cut more than one tape joint at a time! The coiled extensometer behaves like a tight spring and can unwind violently if the tape restraints are not removed sequentially.
  • Page 27 Install Hydraulic Lines (Hydraulic Actuated Anchors Only) Slide the hydraulic line through the hydraulic line hole in the tube mount. Leave enough hydraulic line protruding above the tube mount to attach the hydraulic pump. Lines should be labeled with respect to the corresponding anchor. Bundle the Rods and Anchors Together If desired, use nylon filament tape (provided if the separate tools line was purchased) to loosely bundle the rod and anchor assemblies together.
  • Page 28 Lifting the Extensometer Assembly into the Borehole Connect enough customer supplied rope or cable to the eyebolt(s) located in the top of the tube mount to suspend the extensometer assembly once it is in the borehole. Carefully move the extensometer assembly toward the borehole, create a large arc with the rod tubes of at least 3 meters (10 feet), and then lower the assembly into the borehole.
  • Page 29 Connect the gate valve assembly to the grout pump. It may be advisable to prime the grout tube and verify that it is not plugged by pumping water through the line before grouting. Pump the grout into the borehole slowly, displacing any fluid (water or drilling fluid) left in the borehole.
  • Page 30 3.12 Attach the Transducer Housing Assembly 1) Clean the face of the tube mount. 2) Unscrew and remove the cap screw(s) in the protective cap, then separate the protective cap from the transducer housing. (You will experience some resistance when removing the protective cap due to the O-ring seal provided between the transducer housing and the protective cap.) 3) Make sure the tube mount and transducer housing are properly aligned by matching the...
  • Page 31 5) Rotate the sensor clockwise until it is tight on the connecting rod (about 16 turns). If the transducer is not connecting with the rod below, because of a small misalignment, loosen the Swagelok from the transducer housing and slide it up on the transducer shaft. This allows more flexibility for better alignment.
  • Page 32 3.14 Instrument Head protection The instrument head should be protected from damage wherever possible. This may require recessing the instrument head inside the borehole to avoid blasting or construction-related damage. In exposed locations a protective enclosure can be constructed to ward against falling objects, moving equipment, and vandalism.
  • Page 33 Once installed, the instruments are usually inaccessible and remedial action is limited. Should difficulties arise, consult the following list of problems and possible solutions. For additional troubleshooting and support, contact Geokon. Symptom: Thermistor resistance is too high: ...
  • Page 34 Maximum Length 100 m Table 7 - A-3 Extensometer Specifications ¹The minimum borehole diameter increases with the addition of more measuring points. Please refer to the Model 1100 data sheet for more information. ²Other ranges available on request. A.2 Rod Specifications...
  • Page 35 A.4 Head Assembly Dimensions The dimensions of the Head Assembly of an extensometer can be calculated using Figure 22 Table OPTIONAL FLANGE Figure 20 - Head Assemblies Dimensions, Reference Print...
  • Page 36 Transducer Points Range 12.5, 25, 50 mm 1 point: 404 mm (0.5, 1, 2 inch) 122 mm (15.91 inch) (4.81 inch) 100 mm (4 inch) 440 mm (17.34) inch 1480 mm 2 points: 150 mm (6 inch) 73 mm 88 mm 517 mm 178 mm 57 mm...
  • Page 37 APPENDIX B. THERMISTOR TEMPERATURE DERIVATION Thermistor Type: YSI 44005, Dale #1C3001-B3, Alpha #13A3001-B3 Resistance to Temperature Equation: A+B ( LnR ) +C(LnR) -273.15 °C Equation 1 - Resistance to Temperature Where: T = Temperature in °C. LnR = Natural Log of Thermistor Resistance A = 1.4051 ×...
  • Page 38 APPENDIX C. WIRING CHARTS FOR VIBRATING WIRE TRANSDUCERS C.1 Single Transducer Wiring Chart GEOKON Cable Function / Internal Wiring #02-205V6 Description (Blue) Gauge 1+ Black Black Gauge 1- White Thermistor Black Green Thermistor Shield (1) Table 12 - Wiring for One Transducer C.2 Two Transducer Wiring Chart...
  • Page 39 GEOKON Cable Internal Function / #05-375V12 Wiring Description (Tan) Gauge 1+ Black Black of Red Gauge 1- White Gauge 2+ Black Black of White Gauge 2- Green Gauge 3+ Black Black of Green Gauge 3- Blue Gauge 4+ Black Black of Blue...
  • Page 40 C.6 Six Transducers Wiring Chart GEOKON Cable Internal Function / #012-625V5 Wiring Description (Brown CAB-507) Gauge 1+ Black Black of Red Gauge 1- White Gauge 2+ Black Black of White Gauge 2- Green Gauge 3+ Black Black of Green Gauge 3-...
  • Page 41 APPENDIX D. SWAGELOK TUBE FITTING INSTRUCTIONS These instructions apply to one inch (25 mm) and smaller fittings. D.1 Installation 1) Fully insert the tube into the fitting until it bumps against the shoulder. Figure 21 - Tube Insertion 2) Rotate the nut until it is finger tight. (For high-pressure applications as well as high-safety- factor systems, further tighten the nut until the tube will not turn by hand or move axially in the fitting.) 3) Mark the nut at the six o’clock position.
  • Page 42 D.2 Reassembly Instructions Swagelok tube fittings may be disassembled and reassembled many times. Warning! Always depressurize the system before disassembling a Swagelok tube fitting. 1) Prior to disassembly, mark the tube at the back of the nut, then make a line along the nut and fitting body flats.
  • Page 43 Ordering Information for 1100 Series Standard Extensometer. See Section 1.2, System Components for a detailed description of each component. 1) Extensometer Head Assembly: Specify Part Number from Options A, B & C. 1100 - ______ - ______ - ______ Example: 1100 -...
  • Page 44 Note: One set may be required per overhead extensometer. Hydraulic pump with quick connect for inflating hydraulic anchors. Hydraulic Pump and Hose with Quick Connect:  1100-PUMP: Hydraulic pump with quick connect for inflating hydraulic anchors Standpipe:  1100-#(pts 1-2)-COUPLING: PVC standpipe, 2.5 ft (0.75 m) long, with coupling.
  • Page 45 Grouting: Will the borehole be grouted?  Yes  No General Information: 6 mm (1/4 inch) Rod: Standard rod length is 3 m (10 feet). Optional rod lengths 1.5 m (5 ft.) Considering site conditions and shipping method. 6 mm (1/4 inch) PVC Pipe: Standard PVC pipe length is 3 m (10 ft.). Optional rod lengths 1.5 m (5 ft.) Considering site conditions and shipping method...